Summary of Organization and Significant Accounting policies - Intangible Assets by Type and in Total (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 20,720	$ 17,340
Accumulated Amortization	(3,073)	(2,193)
Net Carrying Amount	17,647	15,147
Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	10,357	10,430
Accumulated Amortization	(2,031)	(1,604)
Net Carrying Amount	8,326	8,826
Reserve Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	9,094	5,890
Accumulated Amortization	(540)	(221)
Net Carrying Amount	8,554	5,669
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,020	1,020
Accumulated Amortization	(470)	(368)
Net Carrying Amount	550	652
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	249
Accumulated Amortization	(32)
Net Carrying Amount	$ 217